Automatic stop mechanism



Mar. 27, 1923 1,449,708

J. TOUCH ET AL AUTOMATIC STOP MECHANISM Filed 001;. 18, 1921 awe/who;

Jab/z 7 0x06. RF". 72666/2.

Patented Mar. 27, 1923.

UNITED STATES PATENT OFFIQE.

JOHN TOUCH AND DOMINIC F. TOUCH, OF ARCHBALD, PENNSYLVANIA.

AUTOMATIC STOP MECHANISM.

Application filed October 18, 1921. Serial No. 508,585.

., provements in Automatic Stop Mechanism,

of which the following is a specification.

This invention relates to automatic stop mechanism and more particularlyto a mechanism designed to stop the operation of an electric motor inthe event of slipping or breakage of a belt or chain driven by saidmotor, or a breakage of any piece of machinery indirectly driven by themotor.

Generally speaking the object of the present invention is to provide inconnection with a line shaft or similar driven part, and an electricmotor for driving said part, means for automatically breaking the motorcircuit in the event the speed of rotation of the shaft is decreasedbeyond a predetermined limit.

The figure of the accompanying drawing represents a view partly inelevation and artl dia rammatic illustratin the mecha-' p y b b wire 14leads to a fixed contact member 17 nism embodying the invention.

In the drawing the numeral 1 indicates an electric motor of any type andthe numeral 2 indicates a line shaft which is driven 'as for example bya belt 3 and pulleys 4 from the shaft of the motor 1. The shaft 2 isdesigned to transmit power to any desired number of machines, and thepresent invention has as its object the provision of means for breakingthe circuit to the motor 1 in the event of breakage or slipping of thebelt 3 or stopping of any of the machines, driven from the line shaft 2,through any accidental cause. The motor circuit is indicated in generalbv the numeral 5 and embraces a knife switch 6 provided with the usualhandle 7 whereby it may be conveniently thrown. This switch ispreferably mounted upon a base block which is indicated by the numeral 8and there is also mounted upon this block an electric motor indicated bythe numeral 9 which motor may be of small size and is provided with theusual shaft 10. A cam 11 is'fixed upon the shaft and, in the rotation ofthe shaft, is designed to ride against one end of a rock lever which isindicated by the numeral 12 and which is pivotally supported as at 13upon the base block 8. The other end of the lever 12 projects beneaththe handle 7 of the knife switch 6 i and when the parts areat rest andin normal positions the cam 11 will be out of engagement with the saidrock lever 12 and the lever will be tilted to about the position shownin the drawing, the switch 6 being closed and the handle 7 of the switchresting in engagement with the last mentioned end of the said rocklever. However, it will be evident that when the motor 9 is energized,the rotation of the shaft 10 of the motor will result in the cam 11 beinbrought into engagement with the end of the rock lever 12 thus rockingthis lever upon its fulcrum and elevatingits end which is engagedbeneath the switch handle 7. This movement of the rock lever will serveto throw the switch to open position and it will remain in this positionuntil again manually closed, at which time, of course, the rock lever 12will be restored to normal position illustrated in the drawing.

The circuit in which the electric motor 9 is located embraces conductorwires 14 and 15, and the wire 15 leads to one terminal of a battery orother source of electric current supply indicated by the numeral 16. The

which is mounted upon some suitable fixed support located in proximityto the shaft 2. A wire 18 leads from the other terminal of the battery16 to a bracket 19 which is also fixed in proximity-to the shaft 2 andsuitably spaced from the contact 17. The numeral 20 indicates in generala governor which is associated with the shaft 2 and this governorcomprises a head 21, which is fixed with relation to the bracket 19 andin electrical circuit therewith, and a head 22 which is slidable uponthe shaft 2, these heads being connected by the usual spring arms 23carrying the centrifugal balls 24.

When the shaft 2 is at rest the head 22 of the governor 20 will be inelectrical contact with the contact member 17 and the circuit will beclosed through the motor 9. When the shaft is rotating, however, at aproper rate of speed, the centrifugal action of the balls 24 of thegovernor will draw the head 22 out of engagement with the contact 17 andno current will flow through the motor 9. Under these conditions, whichare normal, the switch 6 will remain closed to close the circuit throughthe motor 1, but should the belt 3 slip or break or should the speed ofrotation of the shaft 2 for any other reason be retarded below apredetermined limit. the head 22 of the governor 20 will come intoengagement with the contact member 17 thus immediately closing thecircuit through the motor 9 and effecting a rocking movement of thelever 12 to throw the switch 6 to open position thus breaking; thecircuit through the motor 1.

It may at times be desirable to close the circuit through the motor 9from a distant point and with this object in view an elec tricpushbutton switch or a switch of any other suitable type indicated bythe numeral 25 is placed in a shunt circuit 26 with the motor circuit.

It is also preferable that a bell or other signal 27 be placed in ashuntcircuit 28- with the motor circuit so as to give warning at the time thecircuit is closed through the motor 9.

Having thus described the invention,what is claimed as new is:

1. In mechanism of the class described,the combination with a motorcircuit, a motor in said circuit, a switch in said circuit, and anelement driven from the motor, of means operable automatically to throwthe switch to break the motor circuit upon variation in speed of thesaid driven element beyond a predetermined rate, the said meanscomprising a rock lever arranged when rocked in one direction to throwthe switch to break the motor circuit. an electric motor, means operatedthrough said second-mentioned motor for coaction with the rock lever toso move the same, a clrcuitin which the last' mentioned motor islocated, a fixed contact element in the second mentioned circuit, and acontact element also in said second mentioned circuit adapted to bemoved with relation to the first mentioned contact element in accordancewith variation in speed of the said driven element.

2. In mechanism of the class described, the combination with a motorcircuit, a motor in said circuit, a switch in said circuit, and anelement driven from the motor, of means operable automatically to throwthe switch to break the motor circuit upon variation in speed. of thesaid driven element beyond a predetermined rate, the said tion in speedof the said driven element,

and a manually operable switch in the last mentioned circuit for closingthe same in dependently of the contact element.

3. In mechanism of the class described, the combination with a motorcircuit, a motor in said circuit. a switch in said circuit, and anelement driven from the motor, of means operable automatically to throwthe switch to break the motor circuit upon variation in speed of thesaid driven element beyond a predetermined rate, the said meanscomprising a rock lever arranged when rocked in one direction to throwthe switch to break the motor circuit, an electric motor including ashaft, a cam upon the shaft rotatable therewith and ositioned forcoaction with the said rock lever to rock the same when the secondmentioned motor is energized, a circuit in which the lastmentioned motoris located, a fixed contact element in the second mentioned circuit, anda contact element also in said second mentioned circuit adapted to bemoved with relation to the first-mentioned contact element in accordancewith variation in speed of the said driven element.

In testimony whereof we aflix our signatures.

JOHN TOUCH. DOMINIO F. TOUGH.

